Ion conducting composite membrane materials containing an optionally modified zirconium phosphate dispersed in a polymeric matrix, method for preparation of the membrane material and its use

ABSTRACT

The invention provides composite membrane materials comprising a polymer of the state of art uniformly filled with a zirconium phosphate, preferably α-zirconium phosphate or zirconium phosphate sulfoarylenphosphonate particels. The composite membrane materials are preferably prepared starting from a solution of a polymer of the state of art and from a colloidal dispersion of α-zirconium phosphate or a zirconium phosphate sulfoarylenphosphonate. The colloidal particles are transferred into the solution of the polymer preferably by mixing the dispersion with the solution or by means of phase transfer. The membrane material is preferably obtained by removing the solvent by evaporation or by a suitable non-solvent. Besides the composite membrane materials and the preparation methods, the use of the above membrane materials is claimed as ionomeric membranes with high overall performance in high tempreature, especially hydrogen, and in indirect methanol fuel cells and with decreased methanol crossover in direct methanol fuel cells.

Fuel cells (FC) using a proton conducting polymeric membrane as a solidelectrolyte are today the more suitable ones for electrical vehicles andportable electrical devices. As well known, three main types of fuelcells (which usually take the name of the fuel they use) are presentlythe object of an intense research: fuel cells fed with pure hydrogen(hydrogen FC), with hydrogen contained in the reforming gas (“indirect”methanol FC) and with pure methanol gas or an aqueous solution ofmethanol (“direct” methanol FC). The proton conducting membrane plays animportant role so that, in order to have a good performance, specificcharacteristics of the membrane are required for each type of the saidcells. For their high protonic conductivity at low temperature andexcellent chemical stability, perfluorocarboxysulfonic membranes, suchas Nafion, are today the most suitable for hydrogen FC. However, Nafionmembranes are very expensive and, furthermore, their efficiencydecreases at temperatures>70–80° C., due to the difficulty ofmaintaining the whole membrane hydrated at higher temperatures.

The said limitation in the working temperature complicates the coolingof the stacks; furthermore, when Nafion membranes are used in “indirectmethanol FC”, the reforming gas has to be accurately purified from thepresence of carbon monoxide. This is because, especially at lowtemperatures, CO poisons the anodic catalyser. This occurs even atlevels as low as 10 ppm because of the formation of a Pt—CO adduct.However, since this adduct is thermo labile, working temperatures around120–140° C. should be high enough to prevent its formation, thusallowing hydrogen produced by reforming of alkanols or hydrocarbons tobe used as a fuel. Finally, Nafion membranes exhibit high permeabilityto methanol; therefore they cannot be used in “direct” methanol FC.

The problem to obtain polymeric proton conducting membranes combininggood mechanical properties with low methanol permeability and/or highproton conductivity above 70–80° C. can be overcome with at least twodifferent strategies: 1) synthesis of new ionomers possessing thedesired properties, 2) improvement of properties of ionomers of thestate of art by adding inorganic particles which are able to reduce themembrane permeability to methanol, owing to their shape and size, and/orto facilitate (or even increase) the ionomer hydration above 80° C.,owing to their hydrophilic character.

As far as the second strategy is concerned, according to the patent U.S.Pat. No 5,523,181, an improvement of humidification ofperfluorocarboxysulfonic membranes can be obtained by dispersingparticles of silica gel in the above membranes. This modification allowsthe fuel cell to be operated at reduced relative humidity although attemperature below 100° C. Higher working temperatures can be achievedwith a suitable thermal treatment of the silica modified membraneaccording to the patent EP 0 926 754.

Furthermore, according to the international patent WO96/29752, thepermeability to methanol is indeed reduced by adding inorganic particlesamong which, in particular, zirconium phosphate. Relatively to theproblem of an excessive methanol permeability, the recent industrialsuccess in the preparation of nanopolymers filled with organophilicclays clearly indicated that the presence of lamellar particles candecrease to a great extent the gas permeability of the polymeric matrix.This is a consequence of the fact that, during the extrusion process,the lamellar particles tend to orientate themselves parallel to themembrane surface.

As schematically shown in FIG. 1, the presence of suitably orientedparticles (A) modifies the path of the diffusing molecule (B): thelarger the particle surface, the longer the path. It can therefore beexpected that the ionomer permeability to methanol decreases when it isfilled with lamellar particles, in agreement with the effectexperimentally found for zirconium phosphate in the above internationalpatent. However, it can be observed that, in the above patent, theimportance of size and orientation of the lamellar particles was notwell understood. In addition, since zirconium phosphate is completelyinsoluble in known solvents, its insertion was carried out by in situprecipitation. This does not allow to control the orientation, the sizeand the exfoliation of the lamellar particles.

It was therefore recognized the need of inserting zirconium phosphate inionomeric matrices by using a completely different procedure which makesit possible to obtain uniform dispersions of lamellar particles havingdesired size and oriented prevalently parallel to the membrane faces.However, since zirconium phosphate has a relatively low protonconductivity, its dispersion in an ionomer of high proton conductivitymay be associated with a decrease of the overall conductivity,especially for high loadings of inorganic particles.

In order not to decrease, and possibly to increase the ionomerconductivity, there is the need of modifying the proton conductingmembranes of the state of art by dispersing, in the polymeric matrix,lamellar hydrophilic components exhibiting proton conductivitycomparable with, or higher than, the conductivity of the ionomer wherethey have to be dispersed. Since lamellar compounds with high protonconductivity are very insoluble, in this case too it was recognized theneed of finding a procedure, different from the in situ precipitation,suitable to disperse uniformly and with the right orientation lamellarparticles in the polymeric matrix.

It is known from the literature (G. Alberti, M. Casciola, U. Costantino,A. Peraio, E. Montoneri, Solid State Ionics 50 (1992) 315; G. Alberti,L. Boccali, M. Casciola, L. Massinelli, E. Montoneri, Solid State Ionics84 (1996) 97) that some α- or γ-layered zirconium phosphatesulfoarylenphosphonates exhibit proton conductivity up about 0.1 S cm⁻¹.These compounds are represented by the general formulaeZr(O₃POH)_(2−x)(O₃P—Ar)_(x).nH₂O, with 0<x≦2 (α-type compounds), orZr(PO₄)(O₂P(OH)₂)_(1−x)(HO₃P—Ar)_(x).nH₂O, with 0<x≦1 (γ-typecompounds), where Ar is an arylensulfonated group. The inventors haverecognised that these compounds must be considered more hydrophilic thansilica due to the super acidic character of the sulfonic function.

Powders of amorphous zirconium phosphate metasulfophenylenphosphonatesof composition Zr(O₃POH)_(2−x)(O₃P—Ar)_(x).nH₂O, with x=1 and 1.5,supported by sulfonated poly-ether-ether-ketone were already used forthe preparation of composite membranes containing 40% proton conductorwithout any loss of the ionomer conductivity (E. Bonnet, D. J. Jones, J.Rozière, L. Tchicaya, G. Alberti, M. Casciola, L, Massinelli, B. Bauer,A. Peraio, E. Ramunni, J. New Mat. Electrochem. Systems, 3 (2000) 87).Similar results were also obtained for Nafion 1100 membranes loaded withpowder of an α-titanium phosphate metasulfophenylenphosphonate up to 20%(G. Alberti, U. Costantino, M. Casciola, S. Ferroni, L. Massinelli, P.Staiti, Solid State Ionics 145 (2001) 249).

It was now surprisingly found that both amorphous and α- or γ-layeredzirconium phosphate as well as zirconium phosphatemetasulfoarylenphosphonates form stable colloidal dispersions in someorganic solvents (e.g. N,N′-dimethylformamide (DMF),N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide, acetonitrile, alkanols)or in their mixtures with water.

It was also surprisingly found that α-zirconium phosphate Zr(O₃POH)₂,after a suitable process of intercalation-deintercalation ofpropylamine, can be dispersed in dimethylformamide orN-methylpyrrolidone. Moreover, depending on the crystallinity degree ofthe starting material and on the conditions used in the deintercalationprocess, it is possible to obtain dispersions of lamellar particles withthickness ranging from ca. 5 to ca. 100 nm, preferably 5–10 nm, andsurface area from ca. 0.1 to ca. 10 μm², especially 0.2–1 μm².

The availability of the above colloidal dispersions is a good startingpoint to disperse uniformly α-zirconium phosphate or zirconiumphosphate-sulfoarylenphosphonates into a polymeric matrix. In addition,since the size of the lamellar particles in these dispersions depends toa great extent on the size of the particles of the starting material, itis possible to fill the polymeric matrix with lamellar particles ofcontrolled size and shape. As mentioned above, this is a clear advantagein comparison with the in situ formation of α-zirconium phosphatereported in the already cited international patent WO96/7952 and appearsto be particularly important in order to control the reduction ofmembrane permeability to the fuel and specifically to methanol.

It is an object of the present invention to provide a composite membranematerial made of an ionomer of the state of art and of a layeredzirconium phosphate sulfoarylenphosphonate exhibiting protonconductivity comparable with, or possibly higher than, the conductivityof the pure ionomeric membrane material. The conductivity of thezirconium phosphate containing membrane material is >5×10⁻⁴ S cm⁻¹ attemperatures of 0° C. to 200° C. In one embodiment conductivity of amodified zirconium phosphate, especially zirconium phosphatesulfoarylenphosphonate, containing membrane material is >10⁻² S cm⁻¹ at70° C. and 95% relative humidity.

It is a further object of the present invention to provide a compositemembrane material made of an ionomer of the state of art filled withwell-dispersed lamellar particles of α-zirconium phosphate of controlledthickness and surface.

It is a further object of the present invention to provide a procedurefor the preparation of a composite membrane material made of the saidionomer and of a zirconium phosphate, preferably a layered zirconiumphosphate, especially α-zirconium phosphate, or of a zirconium phosphatesulfoarylenphosphonate, starting from a solution of the ionomer and froma colloidal dispersion of α-zirconium phosphate or of the said zirconiumphosphate sulfoarylenphosphonate.

The invention concerns in one aspect the preparation of a colloidaldispersion of α-zirconium phosphate or of a proton conducting zirconiumphosphate sulfoarylenphosphonate in a suitable solvent or mixture ofsolvents, and in the subsequent transfer of the colloidal particles intoa solution of a polymer, especially an ionomer, of the state of art. Themixture thus obtained is cast on the surface of a smooth plane supportand the solvent is removed by heating or by using a suitablenon-solvent. Transfer of the colloidal particles into the polymer,especially ionomer, solution can be carried out (1) by mixing thepolymer, especially the ionomer, solution with the colloidal dispersionor (2) by means of “phase transfer”. It is possible to use nonchargedpolymers as conductivity is contributed by the zirconium phosphate.Preferably there are used ionomers, especially sulfonated polymers dueto their conductivity at low temperatures (<100° C.). There can be usedperfluorosulfonic polymers, especially Nafion, Hyflon or Sterion,sulfonated polyvinylidenfluoride, sulfonated polyetherketones,especially sPEK, sPEEK, sPEKK, sPPEK, sPEEKK or sPEKEKK, sulfonatedpolybenzimidazoles, sulfonated polysulfones sulfonatedpolyphenylsulfones and sulfonated polyethersulfones. In case (1) thesame solvent can be used for the solution and the dispersion.Alternatively, if different solvents are used for the solution and thedispersion, it must be avoided that the solvent of the polymer mayprovoke colloid flocculation and the solvent of the colloidal dispersionmay cause polymer precipitation.

The overall content of zirconium phosphate in the membrane material is0,5%–70%, preferably 5%–40%, especially 10%–25% by weight. For the useas direct methanol fuel cells content of zirconium phosphate is about 10wt %–20 wt %, especially 12 wt % to 15 wt %, were as for hightemperature fuel cells, especially hydrogen fuel cells, a zirconiumphosphate of up to 30 wt %, preferably up to 25 wt %, is used.

For direct methanol fuel cells there is employed a mixture of large andsmall dies, whereas the large dies prevent from methanol permeating themembrane and the small dies prevent from reagglomeration of the largedies. For high temperature fuel cells, especially hydrogen fuel cells,there are employed solely small dies.

The diameter of the large dies is in the range from 0,1 to 1 μm whereasthe diameter of the small dies is about 10–50 nm.

For medium temperature fuel cells dispersed, amorphous as well assemi-crystalline zirconium phosphate is applied. The diameter rages from10–50 nm.

Semi-crystalline zirconium phosphate material enhances mechanicalstability and limits swelling in x- and y-plane. Diameter can be up to100–500 nm.

Crystalline zirconium phosphate material is suitable for direct methanolfuel cells with diameters of 1–10 μm.

The thickness of the zirconium phosphate and zirconium phosphatesulfoarylenphosphonate dies ranges in the scale of single moleculelayers. The overall thickness of the composite membranes is between 10μm and 100 μm, preferably 30–60 μm.

An object of the invention are preferably also membranes comprising thecomposite membrane material for fuel cells or in fuel cells.

Another object of the invention are further fuel cells comprising thecomposite membrane material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the orientation of particles in the composite membranematerial

FIG. 2 shows conductivity behaviour of PFSA+3% ZrP

FIG. 3 shows conductivity of PPEK+20% ZrP

FIG. 4 shows polarisation curve of s-PEEK+20% ZrP compared to Nafion 117

FIG. 5 shows conductivity behaviour of PFS-Li+10% ZrSPP

FIG. 6 shows an 20.000× magnification of s-PEK+20% Zr(SPP)_(1.3)

FIG. 7 shows an 10.000× magnification of s-PEK+10% Zr(SPP)_(1.3)

FIG. 8 shows conductivity of S-PEK+20% ZrSPP

FIG. 9 shows conductivity of s-PEKK+20% ZrSPP

The following examples have the purpose of facilitating theunderstanding of the invention, and do not intend to limit in any mannerits scope, which is solely defined by the appended claims.

EXAMPLES Example 1 Preparation of a Composite Membrane Material made ofSulfonated Polyetherketone/α-zirconium Phosphate by Mixing the IonomerSolution in NMP With a Colloidal Dispersion of α-zirconium Phosphate inDMF

a) A colloidal dispersion of α-zirconium phosphate intercalated withpropylamine(Zr(O₃POH)₂.C₃H₇NH₂) in water is prepared according to G.Alberti, M. Casciola and U: Costantino, J. Colloid and Interface Science107 (1985) 256. The dispersion is treated with 1M HCl so that pH<2. Thesolid is separated from the solution and washed with dimethylformamideunder vigorous stirring. A gelatinous precipitate, containing 4%anhydrous α-zirconium phosphate, settles by centrifugation at 3000 rpm.Washing is repeated up to elimination of chloride ions.

b) A weighed amount of sulfonated polyetherketone with ion exchangecapacity 1.3 meg/g (s-PEK1.3), corresponding to 9 g of anhydrousionomer, is dissolved in NMP under nitrogen atmosphere at 130° C. 25 gof the above gelatinous precipitate of α-zirconium phosphate aredispersed into the polymer solution. This mixture is used to prepare amembrane material by means of an Erichsen semi/automatic film castingprocessor. The solvent is removed by heating 1 hour at 80° C. and 30minutes at 120° C. The membrane material thus obtained (thickness 0.035mm, 10% inorganic particles) is kept in water.

Example 2 Preparation of a Composite Membrane Material made ofs-PEK/Zirconium Phosphate Sulfophenylenphosphonate by Mixing the IonomerSolution in DMF with a Colloidal Dispersion of the Zirconium PhosphateSulfophenylenphosphonate in the Same Solvent.

a) Preparation of Zr(O₃POH)_(0.6)(O₃PC₆H₄SO₃H)_(1.4)

7.5 ml of 1M H₃PO₄ and 15 ml of 1M metasulfophenylenphosphonic acid aremixed and concentrated by heating overnight at 80° C. The dense solutionthus obtained is mixed with 50 ml of acetonitrile and water is addeduntil a clear solution is obtained. 13.6 ml of an aqueous solution of0.75M ZrOCl₂ are then added drop wise to the acetonitrile solution. Thewhite precipitate thus formed is held under vigorous stirring for halfan hour and washed two times with 2M HCl (2×50 ml) and two times withacetonitrile (2×50 ml). The slurry, obtained after centrifugation at3000 rpm, is used for the preparation of a colloidal dispersion in DMF.

b) Preparation of a Colloidal Dispersion ofZr(O₃POH)_(0.6)(O₃PC₆H₄SO₃H)_(1.4) in DMF

A weighed amount of the above slurry is mixed with an equal amount ofDMF and stirred overnight. The mixture is left at rest for one day toallow sedimentation of the solid. The supernatant colloidal dispersioncontains 9% Zr(O₃POH)_(0.6)(O₃PC₆H₄SO₃H)_(1.4), 50% DMF and 41%acetonitrile.

c) Membrane Material Preparation

A weighed amount of s-PEK1.3 (corresponding to 1.2 g of anhydrousionomer) is dissolved under vigorous stirring in 8 g of NMP at 130° C.Subsequently, 3.37 g of the colloidal dispersion described in b) aremixed with 9.05 g of the s-PEK1.3 solution. This mixture is held understirring for half an hour and then cast on a glass plate. The solvent isevaporated as indicated in example 1. The membrane material thusobtained (thickness 0.05 mm, 20% of inorganic material) is kept inwater.

The membrane material conductivity at 100° C. is 1.2·10⁻³ S cm⁻¹ and1.3·10⁻² S cm⁻¹ at 80% and 100% relative humidity, respectively.

Comparative Example 2

The polymer solution used in example 1 is cast on a glass plate. Thefilm thus obtained is heated one hour at 80° C. and half an hour at 120°C. The resulting membrane material is detached by immersing the glassplate in water. The membrane material conductivity at 100° C. is1.1·10⁻³ S cm⁻¹ and 1.1·10⁻² S cm⁻¹ at 80% and 100% relative humidity,respectively.

Example 3 Preparation, by Phase Transfer, of a Membrane Material ofAmorphous Zirconium Phosphate Sulfophenylenphosphonate Dispersed inSulfonated Polyetherketone.

The gelatinous precipitate of example 1a is first heated at 80° C. andthen at 120° C. to remove acetonitrile. An aqueous dispersion of 20%anhydrous zirconium phosphate sulfophenylenphosphonate is held understirring for 1 hour, and then left at rest for two hours to allowsedimentation of the largest particles. The liquid phase is decantedoff. This phase contains 15% Zr(O₃POH)_(0.6)(O₃PC₆H₄SO₃H)_(1.4). Anamount of 1.05 g of s-PEK1.3 is dissolved under vigorous stirring in 8 gof an appropriate solvent, for example, NMP, DMF or dimethylsulfoxide,at 130° C. The above aqueous dispersion is mixed with the polymersolution so that the weight percent of inorganic material in drymembrane material is in the range 1–40%, preferably 5–30%. The lowerboiling solvent is removed by evaporation and the inorganic materialpasses from the aqueous to the organic phase. The single phase productobtained is cast on a glass support and the resulting film dried asdescribed in example 1.

The conductivity of a membrane material containing 10% of inorganicmaterial at 100° C. and 80% relative humidity is 1.3·10⁻³ S cm^(−1.)

Example 4 Preparation of a Perfluorosulfonic Acid (PFSA) Hybrid Membranefor Medium Temperature Fuel Cells Containing 3 wt. % of Amorphousα-zirconium Phosphate (ZrP)

29,12 g of a 10 wt. % solution of the Li-form of the perfluorosulfonicacid polymer PFSA (Nafion®, EW 1150) in N-methyl-2 pyrrolidone (NMP) and1,2 g of a 10 wt. % gel of amorphous exfoliated ZrP in NMP/H₂O are mixedby carefully adding the colloidal dispersion of exfoliated ZrP in smallquantities under vigorous stirring into the PFS-Li solution. Afterfiltration of the mixture through a 10 μm filter, a film is prepared ona glass plate using a doctor blade (gap: 600 μm, feed rate: 10 mm/s).

After applying following drying protocol and delamination from the glassplate, a film of 50–60 μm thickness is obtained.

Drying protocol: 30 min at 50° C., then 30 min at 60° C., then 30 min80° C., then 30 min 120° C.

Before further characterisation, the film was carefully conditioned in1M H₂SO₄, then repeatedly washed in demineralised water until neutral pHwas obtained.

The following conductivity behaviour (FIG. 2) was obtained in atemperature controlled measuring cell under full humidification.

Example 5 Preparation of a Copolyetherketone Hybrid Membrane for DirectMethanol Fuel Cells Containing 20 wt. % of Semi Crystalline α-zirconiumPhosphate (ZrP)

19,45 g of a 15 wt. % solution of the polyphthalazinoneetherketonepolymer (PPEK) (EW 900) in NMP and 5,72 g of a 14 wt.-% gel of semicrystalline exfoliated ZrP in DMF/H₂O is mixed by carefully adding theZrP-gel in small quantities under vigorous stirring into the PPEKsolution. After filtration of the mixture through a 40 μm filter, a filmis prepared on a glass plate using a doctor blade (gap: 600 μm, feedrate: 10 mm/s).

After applying following drying protocol and delamination from the glassplate, a film of 50–60 μm thickness is obtained.

Drying protocol: 30 min at 80° C., then 60 min 120° C.

Before further characterisation, the film was delaminated indemineralised water.

The following conductivity (FIG. 3) is measured in a conductivity cellin 0,5 Mol NaCl and the flux of methanol in a diffusion cell applying afeed concentration of 5 Mol/l CH₃OH versus demineralised water at 50° C.

Example 6 Preparation of a Polyetheretherketone (PEEK) Hybrid Membranefor Direct Methanol Fuel Cells Containing 20 wt. % of Crystallineα-zirconium Phosphate (ZrP)

29,12 g of a 10 wt. % in DMSO solution of the H-form of a sulfonatedVictrex PEEK polymer (EW 735) and 7,3 g of a 10 wt.-% gel of crystallineZrP in DMF/H₂O is mixed by carefully adding the ZrP-gel in smallquantities under vigorous stirring into the s-PEEK solution. Afterfiltration of the mixture through a 40 μm filter, a film is prepared ona glass plate using a doctor blade (gap: 600 μm, feed rate: 10 mm/s).

After applying following drying protocol and delamination from the glassplate, a film of 50–60 μm thickness is obtained.

Drying protocol: 30 min at 60° C., then 30 min at 80° C., then 30 min80° C., then 30 min 120° C.

Before further characterisation, the film was carefully conditioned in1M H₂SO₄, then repeatedly washed in demineralised water until neutral pHwas obtained.

The following polarisation curve (FIG. 4) was obtained compared to aNafion 117 film from Dupont, in a single cell (20 cm²) at 80° C. underDMFC (direct methanol fuel cell)-conditions: Anode 1 Mol/l methanol inwater. Cathode O₂. Electrodes: Anode: 2,4 mg/cm² Pt/Ru; Cathode: 3mg/cm² Pt.

Example 7 Preparation of a Perfluorosulfonic Acid (PFSA) Hybrid Membranefor Medium Temperature Fuel Cells Containing 10 wt. %. of ZirconiumPhosphate Sulfophenylenphosphonate (ZrSPP)

1 g ZrSPP is solubilised in 10 ml H₂O. 20 ml NMP is added and themixture is reduced in volume to 61% at 80° C. A clear solution isobtained. 25 g of a 10 wt. % in NMP solution of the Li-form of theperfluorosulfonic acid polymer PFSA (Nafion®, EW 1150) and 6 g of theafore mentioned ZrSPP solution is mixed by carefully adding theZrSPP-solution in small quantities under vigorous stirring. Afterfiltration of the mixture through a 40 μm filter, a film is prepared ona glass plate using a doctor blade (gap: 600 μm, feed rate: 10 mm/s).

After applying following drying protocol and delamination from the glassplate, a film of 50–60 μm thickness is obtained.

Drying protocol: 30 min at 50° C., then 30 min at 60° C., then 30 min80° C., then 30 min 120° C.

Before further characterisation, the film was carefully conditioned in1M H₂SO₄, then repeatedly washed in demineralised water until neutral pHwas obtained.

The following conductivity behaviour (FIG. 5) was obtained in atemperature controlled measuring cell under full humidification.

Example 8 Preparation of a Polyetherketone (PEK) Hybrid Membrane forMedium Temperature Fuel Cells Containing 10% wt. of Zirconium PhosphateSulfophenylenphosphonate (ZrSPP)

1 g of ZrSPP is solubilised in 10 ml H₂O. 20 ml NMP is added and themixture is reduced in volume to 61% at 80° C. A clear solution of 5 wt.% is obtained. 29,12 g of a 10 wt.-% in NMP solution of the H-form of asulfonated PEK polymer (equivalent weight: 735 g/equivalent) and 14,6 gof the afore mentioned ZrSPP solution is mixed by carefully adding theZrSPP-solution in small quantities under vigorous stirring into thes-PEKK solution.

After filtration of the mixture through a 40 μm filter, a film isprepared on a glass plate using a doctor blade (gap: 600 μm, feed rate:10 mm/s).

After applying following drying protocol and delamination from the glassplate, a film of 50–60 μm thickness is obtained.

Drying protocol: 30 min at 60° C., then 30 min at 80° C., then 30 min80° C., then 30 min 120° C.

Before further characterisation, the film was carefully conditioned in1M H₂SO₄, then repeatedly washed in demineralised water until neutral pHwas obtained.

The following conductivity (FIG. 8) was obtained at reduced humidity(90%). The reference measurement is given as s-PEK.

Example 9 Preparation of a Sulfonated Polyetherketoneketone (s-PEKK)Hybrid Membrane for Direct Methanol Fuel Cells Containing 20 wt. % ofCrystalline Zirconium Phosphate Sulfophenylenphosphonate (ZrSPP)

30,22 g of a 10 wt. % in NMP solution of the polyetherketoneketone(PEKK) polymer (equivalent weight: 775 g/equivalent) and 10,78 g of a 7wt. % gel of amorphous exfoliated ZrSPP in DMF/H₂O is mixed by carefullyadding the ZrSPP-gel in small quantities under vigorous stirring intothe PEKK solution.

After filtration of the mixture through a 40 μm filter, a film isprepared on a glass plate using a doctor blade (gap: 600 μm, feed rate:10 mm/s).

After applying following drying protocol and delamination from the glassplate, a film of 50–60 μm thickness is obtained.

Drying protocol: 30 min at 60° C., 30 min at 80° C., then 60 min 120° C.

The following conductivity (FIG. 9) was obtained in 0,5 Mol NaCl andflux of methanol was measured in a diffusion cell applying a feedconcentration of 5 Mol/l CH₃OH versus demineralised water at 50° C.

1. A method for the preparation of a proton conducting compositemembrane material based on the following steps: a) preparation oflayered particles of zirconium phosphate of the general formulaZr(O₃POH)₂ or zirconium phosphate sulfoarylene phosphonate in the formof a mixture of small and large dies by exfoliation of the phosphates inaqueous solution by intercalation-deintercalation of an alkylamine, b)preparation of a colloidal dispersion of the layered particles in asuitable organic solvent or mixture of organic solvents, c) transferringof the layered particles from the said colloidal dispersion to asolution of a polymer by mixing, d) forming membrane materials withoriented particles by using the obtained mixture and eliminating thesolvent; wherein the particles are exfoliated to a thickness from ca. 5nm to 100 nm.
 2. The method for the preparation of the proton conductingcomposite membrane material according to claim 1 wherein the polymer isan ionomer.
 3. The method for the preparation of the proton conductingcomposite membrane material according to claim 1 wherein the polymer isan ionomer of the membrane material is that of a proton conductingionomer.
 4. The method for the preparation of the proton conductingcomposite membrane material according to claim 1 is at least onesynthetic ionomer selected from the group consisting ofperfluorosulfonic polymers, sulfonated polyvinylidenefluoride,sulfonated polyetherketones, sulfonated polybenzimidazoles, sulfonatedpolyphenylsulfones, sulfonated polysulfones and sulfonatedpolyethersulfones.
 5. The method for the preparation of the protonconducting composite membrane materials according to claim 1 wherein themixture containing the polymer and the layered particles is obtained bymixing the ionomer solution with the colloidal dispersion of the layeredparticles.
 6. The method for the preparation of the proton conductingcomposite membrane material according to claim 1 wherein the colloidaldispersion of the layered particles is obtained by using at least oneorganic solvent selected from the group consisting ofN,N′-dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide,acetonitrile and alkanols, preferably N,N′-dimethylformamide and/orN-methyl-2-pyrrolidone, or their mixtures or water or mixtures of waterand organic solvent.
 7. The method for the preparation of the protonconducting composite membrane material according to claim 1 wherein aionomer solution and the colloidal dispersion are prepared in the samesolvent or in different solvents, provided that the mixing of thesolution with the dispersion does not cause colloid flocculation orionomer precipitation.
 8. The method for the preparation of the protonconducting composite membrane material according to claim 1 wherein themixture containing an ionomer and the layered particles is obtained by“phase transfer”.
 9. The method for the preparation of the protonconducting composite membrane materials according to claim 1 wherein thesolvent is removed from the polymer-colloid mixture by evaporation. 10.The method for the preparation of the proton conducting compositemembrane material according to claim 1 wherein the solvent is removedfrom the polymer-colloid mixture by the use of a non-solvent.
 11. Themethod for the preparation of the proton conducting composite membranematerial according to claim 10 wherein the non-solvent is water.
 12. Amethod for the preparation of the proton conducting composite membranematerial based on the following steps: a) preparation of layeredzirconium phosphate sulfoarylene phosphonate in the form of a mixture ofsmall and large particles by direct exfoliation in aqueous solution byintercalation-deintercalation of an alkylamine, b) preparation of acolloidal dispersion of the layered particles in a suitable organicsolvent or mixture of organic solvents, c) transferring of the layeredparticles from said colloidal dispersion to a solution of a polymer bymixing, d) forming membrane materials with oriented particles by usingthe obtained mixture and eliminating the solvent; wherein the particlesare exfoliated to a thickness of ca. 5 nm to 100 nm.
 13. The method forthe preparation of the proton conducting composite membrane materialaccording to claim 12 wherein the polymer is an ionomer.
 14. The methodfor the preparation of the proton conducting composite membrane materialaccording to claim 12 wherein the polymer is an ionomer of the membranematerial is that of a proton conducting ionomer.
 15. The method for thepreparation of the proton conducting composite membrane materialaccording to claim 12 is at least one synthetic ionomer selected fromthe group consisting of perfluorosulfonic polymers, sulfonatedpolyvinylidenefluoride, sulfonated polyetherketones, sulfonatedpolybenzimidazoles, sulfonated polyphenylsulfones, sulfonatedpolysulfones and sulfonated polyethersulfones.
 16. The method for thepreparation of the proton conducting composite membrane materialsaccording to claim 12 wherein the mixture containing the polymer and thelayered particles is obtained by mixing the ionomer solution with thecolloidal dispersion of the layered particles.
 17. The method for thepreparation of the proton conducting composite membrane materialaccording to claim 12 wherein the colloidal dispersion of the layeredparticles is obtained by using at least one organic solvent selectedfrom the group consisting of N,N′-dimethylformamide,N-methyl-2-pyrrolidone, dimethylsulfoxide, acetonitrile and alkanols,preferably N,N′-dimethylformamide and/or N-methyl-2-pyrrolidone, ortheir mixtures or water or mixtures of water and organic solvent. 18.The method for the preparation of the proton conducting compositemembrane material according to claim 12 wherein a ionomer solution andthe colloidal dispersion are prepared in the same solvent or indifferent solvents, provided that the mixing of the solution with thedispersion does not cause colloid flocculation or ionomer precipitation.19. The method for the preparation of the proton conducting compositemembrane material according to claim 12 wherein the mixture containingan ionomer and the layered particles is obtained by “phase transfer”.20. The method for the preparation of the proton conducting compositemembrane materials according to claim 12 wherein the solvent is removedfrom the polymer-colloid mixture by evaporation.
 21. The method for thepreparation of the proton conducting composite membrane materialaccording to claim 12 wherein the solvent is removed from thepolymer-colloid mixture by the use of a non-solvent.
 22. The method forthe preparation of the proton conducting composite membrane materialaccording to claim 21 wherein the non-solvent is water.